FXLS8471Q Datasheet, PDF (54/75 Pages) Freescale Semiconductor, Inc – Linear Accelerometer

Table 89. A_FFMT_COUNT relationship with the ODR
ODR (Hz)
800
400
200
100
50
12.5
6.25
1.56
Normal
0.319
0.638
1.28
2.55
5.1
5.1
5.1
5.1
Max time range (s)
LPLN
High
resolution
0.319
0.319
0.638
0.638
1.28
0.638
2.55
0.638
5.1
0.638
20.4
0.638
20.4
0.638
20.4
0.638
Low power
0.319
0.638
1.28
2.55
5.1
20.4
40.8
40.8
Normal
1.25
2.5
5
10
20
20
20
20
Time step (ms)
LPLN
High
resolution
LP
1.25
1.25
1.25
2.5
2.5
2.5
5
2.5
5
10
2.5
10
20
2.5
20
80
2.5
80
80
2.5
160
80
2.5
160
For example, an ODR of 100 Hz and a A_ FFMT_COUNT value of 15 would result in minimum debounce response time of
150 ms.
Low-g Event on
all 3-axis
Count Threshold
FF Counter
EA
Low-g Event on
all 3-axis
Count Threshold
Debounce Counter
EA
(a)
a_ffmt_dbcntm = 1
(b)
Low-g Event on
all 3-axis
Count Threshold
Debounce Counter
a_ffmt_dbcntm = 1
(c)
EA
Figure 17. Behavior of the A_FFMT debounce counter in relation to the a_ffmt_dbcntm setting
FXLS8471Q
54
Sensors
Freescale Semiconductor, Inc.